This invention is in the field of laminated parts and their manufacture and more particularly electric motor or generator rotor and stator stacks and their manufacture.
Laminated rotors and stators manufactured by stacking laminas are well known in the art. Typically, the laminas are blanked from continuous strip stock and are then stacked and interlocked to form the rotor or stator stack, which are referred to as cores. U.S. Pat. Nos. 4,738,020 and 4,619,028 assigned to the assignee of the instant application describe an apparatus and method for manufacturing laminated stacks.
During manufacture of the lamina which are used for preparing the stacks, a device is used to measure the thickness of the strip stock used for construction. A particular problem encountered is with the consistency of the stock readings which, when inaccurate, may lead to errors in a particular direction that will cause the stacked cores to be either too light or too heavy. Even a small error in stock thickness gets compounded by the number of laminas in the stack.
An associated problem is created when a long core is manufactured from a strip stock which is too thick. The stack will be too high and this can damage the core handling apparatus because of the core's extra weight and height. Basically, it is a failure of the equipment to cut the stack off at the proper stack size due to variations of the strip stock material thickness. Manual adjustments, excessive scrap and excessive adjustment time have resulted from inaccurate stock measurements.